A treating fluid may contain an effective amount of a particulate additive to fixate or reduce fines migration through a particular zone, bed or pack as described in U.S. Patent Application Publication No. 2009/0312201 A1, incorporated by reference herein in its entirety. The particulate additive may be alkaline earth metal oxides, alkaline earth metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, post-transition metal hydroxides, piezoelectric crystals and pyroelectric crystals. The particle size of the magnesium oxide or other agent may be nanometer scale, which scale may provide unique particle charges that help fixate the formation fines. Such particles may be termed nano-sized particles or nanoparticles herein. These treating fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in hydraulic fracturing, completion fluids, gravel packing fluids and fluid loss pills. The carrier fluid used in the treating fluid may be aqueous, brine, alcoholic or hydrocarbon-based.
In related technology, a fracturing fluid, gravel pack fluid and/or frac pack fluid containing particles such as proppants, gravel and/or sand, may also contain an effective amount of a nano-sized particulate additive to fixate or reduce fines migration therethrough, where the particulate additive may again be alkaline earth metal oxides, alkaline earth metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, post-transition metal hydroxides, piezoelectric crystals and pyroelectric crystals. The nano-sized particulate additives are coated onto or associated with the gravel or proppant particles during application with a coating agent such as an oil. The particle size of the magnesium oxide or other agent may be nanometer scale, which scale may provide unique particle charges that help fixate the formation fines that come into contact with the bed of proppant, gravel or sand in the fracture. Again, the carrier fluid used in the treating fluid may be aqueous, brine, alcoholic or hydrocarbon-based. More details may be found at U.S. Pat. No. 7,721,803, incorporated by reference herein in its entirety.
It has also been discovered that nanoparticle-treated particle packs, such as sand beds, may effectively filter and purify liquids such as waste water. These packs and beds and methods for using them are described in U.S. Patent Application Publication No. 2009/0266766 A1, incorporated by reference herein in its entirety. When tiny contaminant particles in waste water flow through the particle pack, the nanoparticles in the pack will capture and hold the tiny contaminant particles within the pack due to the nanoparticles' surface forces, including, but not necessarily limited to, van der Waals and electrostatic forces. Coating agents such as alcohols, glycols, polyols, vegetable oil, and mineral oils may help apply the nanoparticles to the particle surfaces in the filter beds or packs.
However, in all of these treatment methods, at some point the nanoparticle-treated pack, bed or zone approaches its maximum capacity for capturing fines and inhibiting their flow from a formation through a particle pack into a wellbore, or its maximum capacity for removing contaminants in the waste water flowing through the pack or bed. It would thus be desirable if methods, techniques and/or compositions would be devised to regenerate and/or recharge the nanoparticle-treated particle packs so that their usefulness may be prolonged.